Anybody know what Blackmagic means by "4K" in terms of the actual, specific resolution of the video files? I know there's a "4 times 1080p pixels" flavor of 4k then there's some broadcast 4K standard that is actually over 4,000 pixels wide. Thanks!

Its native resolution is 3840 x 2160, so it's UHD, rather than Cinema 4K (4096 wide).

Frankly, that's not a big deal. It's only a 6% resolution difference. The bigger limitation is that a Bayer sensor at 3840 won't offer the full resolution possible for UHD. The true resolution will be more like 3K, depending on the anti-aliasing filter in the camera and the de-Bayer software quality.

The problem is this: if you don't anti-alias before the signal hits the pixels, you can get content that falls between the cracks. Yes, the cracks are larger in a DSLR, but anti-aliasing is always important when you go from analog to digital. It's especially important for moving pictures where high frequency content can make the image "sing".